Topping-up arrangements for multi-cell electric batteries

ABSTRACT

A topping-up arrangement for multi-cell electric storage battery comprises a vent extending down into each cell to a point below the desired liquid level, and a small filling opening into each cell from a common filling trough, of such size that a meniscus will form. A removable common cover for the trough carries a number of probes, one projecting down through each filling opening the probe being so shaped as to permit air to escape while liquid drains into the cell.

United States Patent 1191 Painter et al.

[54] TOPPING-UP ARRANGEMENTS FOR MULTl-CELL ELECTRIC BATTERIES [75]Inventors: Roy Painter, Smallshaw, Ashtonunder-Lyne; Graham JohnVaughan, Swinton, near Manchester, both of England [73] Assignee:Electric Power Storage Limited,

Manchester, England [22] Filed: Aug. 21, 1970 [21] Appl. No.: 65,970

[52] US. Cl. ..136/170, 136/178, 136/182 [51] Int. Cl. ..H01m H02 [58]Field of Search ..l36/l62, 170, 177, 178, 182

[56] References Cited UNITED STATES PATENTS 2,306,569 12/1942 Sandusky..l36/178 law [4 1 Jan. 2, 1973' 3,485,678 12/1969 Blaich m1 ..l36/l70FOREIGN PATENTS 0R APPLICATIONS 635,716 H1962 Canada ,.l36/l78 PrimaryExaminerDonald L. Walton Attorney-Watson, Cole, Grindle & Watson [57]ABSTRACT A topping-up arrangement for multi-cell electric storagebattery comprises a vent extending down into each cell to a point belowthe desired liquid level, and

a small filling opening into each cell from a common 13 Claims, 8Drawing Figures PATENTEDJAH 2 am 3.708.348

SHEET 2 [IF 2 FIG. 4 H65 FIG. 6.

Gamma J0me Mann BY ATT TOPPING-UP ARRANGEMENTS FOR MULTI- CELL ELECTRICBATTERIES This invention relates to topping-up arrangements formulti-cell electric storage batteries and is concerned with theprovision of a simple arrangement for facilitating one-shot topping-upof a number of cells.

According to the present invention the arrangement includes a vent foreach cell open to atmospheric pressure and extending down into the cellto slightly below the desired level of the electrolyte, a trough commonto a number of cells and extending over the top of them, a fillingopening from the trough into each cell, of such size that a meniscuswill form across the hole preventing air-from escaping through it whileliquid is entering through it, and a probe adapted to extend througheach opening and shaped so as to permit air to escape while the liquiddrains through the opening. The probe is preferably of such section asto partially enclose a volume of fluid and may comprise a pair ofopposed walls. Thus a probe which is of a section having in it one ormore grooves may be employed, for example a Y, T or cruciform section ora C or U section.

The diameter of the opening may be between 4 mm and 8 mm but preferablybetween 6 mm and 7.5 mm. It is desirable that the probe is of sufficientlength to extend at least mm below the bottom of the opening and thatthe size of the probe in relation to the opening is such as to leave aclearance between them. The clearance being not less than 1.16 mm in thecase of a C or U section. The lower end of the probe may be pointed.

Preferably, the probes for all or a number of cells are carried by acover for covering the trough serving those cells.

Further features and details of the invention will be apparent from thefollowing description of one specific embodiment and modifications thatwill be given by way of example with reference to the accompanyingdrawings in which:

FIG. 1 is a sectional elevation of part of a battery lid and covershowing the topping-up arrangement,

FIG. 2 is a plan view of a battery lid with the cover removed,

FIG. 3 is a perspective view of part of the lid and cover shown in FIG.1, and

FIGS. 4 to 8 are cross-sectional views of probes having C, U, T, Y, andcruciform sections respectively.

In the embodiment the invention is applied to a motor-car startingbattery, having, for example, six cells. The battery has a monobloc lid10 formed with a trough 11 extending over all the cells for topping-up.Projecting up from the bottom of the trough 11 are a row of ventingtubes 12 each of which extends down into one of the cells to slightlybelow the desired level of electrolyte. The desired level is indicatedby the chain line 16 in FIG. 1.

Alongside each venting tube 12 is a filling opening 13 of such size thata meniscus can form to prevent air escaping through it while liquid isentering the cell through it from the trough 11. Typically an opening of6.35 mm diameter is found suitable.

The trough 11 is provided with a flat cover 21 which fits nearly flushwith the surrounding surface of the lid 10 and is located by a recess 14in the lid/or alternatively by two or more projections (not shown) whichfit into certain of the venting tubes. The cover 21 carries a row of sixprobes or quills 22 each projecting down and extending through one ofthe filling openings 13 when the cover is placed in position. Each probe22 is of tubular form (of outside diameter 5.1 mm) having a singlelongitudinal slit 23 extending throughout its length so as to produce aprobe of C or U section (shown in FIGS. 4 and 5 respectively), and, whenin position, it extends down to a point about 11 mm below the undersideof the trough, electrolyte.

Accordingly, the operation is as follows: In order to top-up the batterythe cover 21 is removed and water is poured into the trough 11. Thewater flows down through the filling openings 13 while air escapesthrough the venting tubes 12. As the level in each cell approaches thedesired level 16, the underside of the venting tube 12 is closed by theliquid so that air can no longer escape through it. Asalready indicatedthe size of the filling opening is such that a meniscus can form acrossit preventing air from escaping through it while liquid is enteringthrough it, so that an air lock is formed and no further liquid entersthe cell. After all the cells have reached this condition, water beginsto rise in the trough 11, and the user stops pouring, for example whenthe water level in the trough reaches an appropriate mark. This leaves asmall quantity of liquid in the trough. The user then puts the cover 21on the trough and when the probes 22 enter the filling openings, it isfound that they break the meniscus in each opening and allow the liquidremaining in the trough to drain into the cells.

The size of each filling opening and the shape of the probe are suchthat the liquid drains into the cells as soon as the cover carrying theprobes is placed in position, although in some cases it may besufficient if, with the cover in place, the liquid drains from thetrough as soon as the complete battery is vibrated, for example due tomovement of a vehicle in which the battery is installed. It is importantthat the liquid should drain in use since on the one hand pure waterremaining in the trough is liable to freeze in cold weather, and inaddition if gassing occurs the electrolyte may be forced up through thevent tubes and may find its way out from under the cover. In addition ifthe battery was topped up in extremely low temperature conditions, andremained for a long period in a stationary vehicle, the layer of purewater on top of the electrolyte could freeze and seal both the fillingopening and the vent opening of each cell.

To ensure satisfactory draining, each filling opening should not be toobig, say more than about 8 mm diameter, to ensure that the liquid willnot drain through it before the probe is inserted, resulting inover-filling. Conversely if the opening is too small, say less than 4 mmdiameter, filling may be rather slow and there may be difficulty ingetting a probe to give reliable draining.

The section of the probe also has an influence on draining, and ingeneral it is thought that it should be such as to partially enclose avolume of liquid, for example between a pair of opposed walls or in agroove. Thus a pair of parallel strips has been found to function, ashave probes of cruciform, T or Y section (shown in FIGS. 8, 6 and 7respectively) and the probes shown in FIGS. 1 and 3 which as referred toabove and shown in FIGS. 4 and 5 are of C or U section.

It appears important that the size of the probe in relation to theopening should be such as to leave a clearance round it, for example atleast a 1 mm. It is also important that the probe should extend beyondthe bottom of the filling opening to an appreciable distance, say notless than mm while the open groove extends above the liquid surface. Asdescribed above the end of the probe may be pointed.

A solid rod or a tube has not been found to achieve draining and othershapes have given unreliable results.

The invention is not dependent on any particular theory of operation,and indeed it is observed that sometimes a bubble of air travels up theinside of the probe (the liquid presumably descending outside it) andsometimes vice versa. It is believed that, at least on some occasions,it is a requirement that the probe should divide the surface of theliquid into two areas which do not merge to such an extent that onecannot descent without dragging the other with it by surface tension,and hence one can descend without the other,

the descending liquid column being replenished until it exerts anappreciable head to overcome surface tension and force a bubble ofliquid up the other column.

What we claim as our invention and desire to secure by Letters Patentis:

l. A storage battery having means for topping-up the electrolyte to adesired level, comprising:

a number of cells housed within said storage battery; a lid for coveringsaid storage battery and including a vent for each cell open toatmospheric pressure and extending down into the cell to slightly belowthe desired level of the electrolyte; said lid further including atrough for receiving liquid and extending over the top of said cells; afilling opening extending through said trough into each cell and havinga diameter so that a meniscus will form across said opening with liquidin said trough preventing air from escaping from said opening; and

a cover for covering said trough and including a probe extending througheach said opening and having one or more grooves to permit air to escapeas the liquid in said trough drains through said opening with said coveron said lid.

2. A storage battery as in claim 1 in which said probe comprises a pairof opposed walls for enclosing a volume of liquid therebetween.

3. A storage battery as in claim 1 in which the diameter of each saidopening is between 4 mm and 8 mm.

4. A storage battery as in claim 3 in which the diameter of said openingis between 6 mm and 7.5 mm.

5. A storage battery as in claim 1 in which said probe is of sufficientlength to extend at least 10 mm below the bottom of said opening.

6. A storage battery as inclaim l in which the size of said proberelative to said opening is such as to leave a clearance therebetween.

7.. A storage battery as in claim 6 in which said clearance is not lessthan 1.16 mm.

8. A storage battery as in claim 1 in which the lower end of said probeis pointed.

9. A storage battery as in claim 1 wherein said probe has a Y"cross-section.

10. A storage battery as in claim 1 wherein said probe has a Tcross-section.

11. A storage battery as in claim 1 wherein said probe has a Ucross-section.

12. A storage battery as in claim 1 wherein said probe has a "C"cross-section.

13. A storage battery as in claim 1 wherein said probe has a cruciformcross-section.

UNITED STATES PATENT ()FFICE -=-G ERTIFICATE OF CORRECTWN Patent No.,708,348 Dated January 2, 1973 Inventor-(s) Roy Painter and Graham JohnVaughan It is certified that error appears in the above-identifiedpatent and that said Letters Patent are hereby corrected as shown below:

7 Foreign Application Priority Data August 21, 1969 Great Britain N41834/69 (SEAL) Attest:

EDWARD M.FLETCHER,JR.

Rene Tegtmeyer Attestlng Officer Acting Commissioner of Patent:

F ORM PO-105O (10-69) v USCOMM-DC 60376-P69 Q U-S. GOVERNMENT PRINTINGOFFICE I969 O-'366-!34,;

1. A storage battery having means for topping-up the electrolyte to adesired level, comprising: a number of cells housed within said storagebattery; a lid for covering said storage battery and including a ventfor each cell open to atmospheric pressure and extending down into thecell to slightly below the desired level of the electrolyte; said lidfurther including a trough for receiving liquid and extending over thetop of said cells; a filling opening extending through said trough intoeach cell and having a diameter so that a meniscus will form across saidopening with liquid in said trough preventing air from escaping fromsaid opening; and a cover for covering said trough and including a probeextending through each said opening and having one or more grooves topermit air to escape as the liquid in said trough drains through saidopening with said cover on said lid.
 2. A storage battery as in claim 1in which said probe comprises a pair of opposed walls for enclosing avolume of liquid therebetween.
 3. A storage battery as in claim 1 inwhich the diameter of each said opening is between 4 mm and 8 mm.
 4. Astorage battery as in claim 3 in which the diameter of said opening isbetween 6 mm and 7.5 mm.
 5. A storage battery as in claim 1 in whichsaid probe is of sufficient length to extend at least 10 mm below thebottom of said opening.
 6. A storage battery as in claim 1 in which thesize of said probe relative to said opening is such as to leave aclearance therebetween.
 7. A storage battery as in claim 6 in which saidclearance is not less than 1.16 mm.
 8. A storage battery as in claim 1in which the lower end of said probe is pointed.
 9. A storage battery asin claim 1 wherein said probe has a ''''Y'''' cross-section.
 10. Astorage battery as in claim 1 wherein said probe has a ''''T''''cross-section.
 11. A storage battery as in claim 1 wherein said probehas a ''''U'''' cross-section.
 12. A storage battery as in claim 1wherein said probe has a ''''C'''' cross-section.
 13. A storage batteryas in claim 1 wherein said probe has a cruciform cross-section.